Apparatus for registering transparencies in printing frame



Jan. 14, 1958 T. A. DEXTER 2,819,535

APPARATUS FOR REGISTERING TRANSPARENCIES IN PRINTING FRAME Filed F91). 17, 1954 20 AT TOR/VEYS United States Patent C) APPARATUS FOR REGISTERING TRANS- PARENCIES IN PRINTING FRAME Thomas A. Dexter, Pearl River, N. Y.

Application February 17, 1954, Serial No. 410,878

7 Claims. (Cl. 333-1845) This invention relates to apparatus for making color prints by means of two or more different color plates. The invention relates more especially to the obtaining of improved registration for the printing of the successive colors.

One object of the invention is to provide improved apparatus for accurately locating negatives with respect to different plates at the time when the plates are exposed to light transmitted through the negative; and another object is to provide a combination of structure for obtaining such improved results with conventional vacuum frames which are standard equipment in most photootlset shops.

in accordance with one feature of the invention, a group of fixed abutments are provided at locations for simultaneously positioning the light-sensitive plate and a negative carrier in an exposure frame, and preferably a conventional vacuum frame. Another feature of the invention combines a supporting panel, which can be placed on the pad of the vacuum frame, with location abutments secured to the panel at fixed locations, but with detachable fastening means which permit movement of the abutments into different fixed positions to accommodate plates and negative holders of different size.

Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.

in the drawing, forming a part hereof, in which like reference characters indicate corresponding parts in all the views:

Fig. l is a perspective view showing a photo printing frame embodying this invention,

Fig. 2 is an enlarged, top plan view of the panel shown in Fig. l, with a plate and a color separation negative positioned thereon,

Figs. 3 and 4 are views showing other color separation negatives which are used in conjunction with the negative of Fig. 2,

Fig. 5 is an enlarged, fragmentary top plan view, of the structure shown in Fig. 2 with the details of the abutment brought out by the larger scale; and

Pig. 6 is an enlarged sectional view taken on the line ti -6 of Fig. 5.

This invention is intended for use with a conventional vacuum printing frame of the type commonly used for photo exposure work. A simplified form of such a frame is diagrammatically shown in Fig. l. The frame includes a body 19 supported from the floor by legs 11. The top of the body is recessed to provide a chamber 13, and there is a cover which closes the upper end of the chamber 13 when the cover is in its lowered position. The cover 15 is connected to the body 10 by hinges, and it has a transparent window 17 extending over substantially the entire area of the chamber 13.

Within the chamber there is a mat or pad 20 which is commonly made of rubber. When the apparatus is used as a vacuum printing frame, there is an air pump connected with the space above the mat or pad 2t) for operating the frame in a manner well understood in the 2331 19535 Patented Jan. 14, 1958 art, the structure of the printing frame, thus far described, being conventional.

When combining this invention with the printing frame, a panel 22 is located on the pad 20 under the window 17. The pad 20 is preferably made of Wood or plastic material which is substantially uncompressible in the direction in which the panel extends across the pad 20. There are protuberances 2 (Fig. 6) extending upwardly from the pad 20 and it is these protuberances of the rubber mat or pad 20 which actually support the panel 22.

In order to provide flexibility, in directions transverse of the extent of the panel across the pad 20, a number of spaced grooves 26 are provided in the top surface of the panel 22 extending in different directions. In the construction shown, these grooves 26 are evenly spaced and the angular relation is a right angle so that the grooves 236 divide the top surface of the panel into a multitude of small squares; but it will be understood that other relations of the grooves can be provided for obtaining the intended flexibility.

The purpose of the flexibility of the panel 22 is to insure contact of the panel with the mat or pad 20 over the entire area of the bottom face of the panel. The grooves 26 have a depth somewhat less than one-half the thickness of the panel 22.. Deeper or shallower grooves can be used but the depth must be sufiiciently limited to pro vent the top surface of the panel from having a shifting movement with respect to the bottom face or side edges.

There are abutments 31, 32 and 33 at spaced locations over the panel 22. These abutments are preferably connected to the top surface of the panel 22 by detachable fastening means so that the positions of the abutments 31-33 can be changed to suit work of different sizes.

The purpose of the abutments 3l33 is to position plates and different color separation negatives with great accuracy so as to insure perfect registration in the subsequent printing. Fig. 2 shows a sensitized sheet or plate 35 located on the panel 22, and shows a negative carrier 36 for supporting color separation negatives 38, 39 and 40.

The negative carrier 36 is a transparent uncompressible plastic sheet of sufficient thickness to be easily handled without wrinkling but thin enough to be flexible so that it will lie fiat on the sensitized plate 35. The negatives 38 and 40 are located on and secured in place on, the carrier 36 by registering the carrier with a transparent plate having master registration marks thereon, at the time When the negatives are being attached to the negative carrier 36.

The sensitized plate 35, which may be a zinc printing plate, such as commoniy used for offset printing, is located in position on the panel 22 by bringing the bottom edges of the plate against the abutments 31 and The transverse positioning of the plate is determined by bringing the adjacent, right hand edge of the plate against the abutment 33. By having the abutments 331, 3?; and 33 securely fixed in their positions on the panel 22, each sensitized plate can be similarly located, with greater exactness before exposure. The negative carrier 36, placed on top of the sensitized plate 35, and before exposure of the plate, is accurately positioned in the same way, by bringing the bottom edge of the negative carrier 36 against the abutments 31 and 32, and the right hand edge of the negative carrier against the abutment 33.

The longer the distance is between the abutments 31 and the more accurate the positioning of the plate and carrier will be, but it is evident that the spacing of the abutments 31 and 32 cannot be greater than the width of the particular plate and negative carrier which are being positioned on the panel. In order to have the abutments 3l33 movable into the most advantageous positions for the particular sizes of the plate and the 3 carrier which are to be used for a run of exposures, abutments 3l---33 are detachably connected to the panel 22, though the fastening means hold them rigidly in place while attached to the panel.

Fig. 3 shows a negative carrier 46, which is similar to the negative carrier 36, but which has color separation negatives 49 and 50 which are used in conjunction with the color separation negatives 39 and 40 of the negative carrier 36 shown in Pig. 2.

Fig. 4 shows another plastic sheet, negative carrier 53 with color separation negatives 56, 57 and 58 thereon corresponding with the similarly located color separation negatives on the other plastic sheet, negative carriers 36 and 4-6, of Figs. 2 and 3, respectively.

Some features of the invention can be used with negatives other than those mounted on the negative carrier of this invention, and the term negative will be used, in the subsequent description and the claims, in a broad sense to denote either an individual negative or a transparent negative carrier having one or more separate negatives secured thereto.

Figs. 5 and 6 show the construction of the individual abutments 3t, 32 and 3.3. The construction will be described in connection with the abutment 33, but it will be understood that the other abutments, are of similar construction. The abutment 33 includes a block 61, preferably made of metal and silver soldered to a thin metal plate 62 which is approximately .003 to .006 of an inch in thickness. This abutment plate 62 rests on the top face of the panel 22, and it extends beyond both the inner and outer faces of the block 61.

The thin metal bottom plate 62 rests upon the top face of the panel 22 and it is held in a fixed position on the panel by adhesive tape 64 which extends across the plate 62 and across adjacent portions of the top face of the panel 22. The adhesive tape 64 adheres to the top surface of the metal sheet 62 and to the top face of the panel 22. This holds the abutment securely in position because the adhesive tape has great strength against shearing displacement forces. However, the tape 64 can be a pressure sealing tape so that it can be easily removed by pulling it away from the panel, whenever it becomes necessary to change the location of the abutment. Thus, the tape comprises a detachable fastening means for holding the abutment on the panel.

The height of the block 61, of the abutment, is equal to the combined heights of the plate 35 and the negative, 36, and there is a retaining means 66 at the top of the abutment extending out over the top surface of the negative 36. This retaining means comprises a thin sheet of metal, preferably steel, having a thickness of approximately .005. This retaining plate 66 holds the negative 36 in contact with the plate 35 at the region of the abutment and insures that both the plate 35 and the negatives 36 are in contact with the inside face of the block 61.

From the foregoing description it will be apparent that the abutments 31, 32 and 33 including the blocks, and their plates 62 and retaining means 66 are free of the sheet and negative, that is, they are not connected to the sheet and negative, thus leaving the sheet and negative movable with respect to the abutments when positioning the sheets and negative. It cannot be said accurately that the abutments are separate from the sheets and negative because they may touch and sometimes do; and the expression free of merely means that the sheets and negative are not connected to, and can be moved independently of, the abutments up to contact of the sheet and negatives with the abutments as limit or positioning stops.

The preferred construction has been illustrated and described, but changes and modifications can be made without departing from the invention as defined in the claims.

What is claimed is:

1. Photo exposure apparatus comprising a vacuum printing frame having a supporting panel for a sensitized sheet and an overlying negative, positioning abutments free of the sheet and negative and extending over portions of the panel, detachable fastening means connecting the positioning abutments to the panel, there being two abutments at spaced locations in position to contact with a corresponding edge of both the sheet and negative and another positioning abutment in position to contact with corresponding adjacent sides of the sheet and negative when the sheet and negative are in position for exposure in the printing frame, the abutments being of a height substantially equal to the combined height of the sheet and negative, and a thin plate extending from the top of at least one of the abutments and across a part of the negative and free of said negative.

2. A photo exposure apparatus including a vacuum printing frame having a resilient pneumatically operated pad therein, a supporting panel on the pad, the panel being rigid in directions of its extent across the pad, positioning abutment means on the panel, detachable fastening means connecting the abutments to the panel, there being two abutments spaced from one another in one direction, and a third abutment located along a line at an angle to a line extending between the first two abutments, a negative carrier comprising a light transmitting sheet having a length at least as great as the spacing of the abutment means and having edges that contact with the abutment means to accurately position the negative carrier over a sensitized plate positioned on the panel by contact of its edges with the abutment means, and a thin plate extending from the top of at least one of the abutments and across a part of the negative carrier and free of said negative carrier.

3. The photo exposure apparatus described in claim 2 characterized by a negative carrier which is made of plastic material and which is flexible in directions transverse of its extent but substantially uncompressible in directions parallel to the plane of its top and bottom faces.

4. Photo exposure apparatus including a vacuum printing frame having a resilient pad therein, a supporting panel mounted on the resilient pad, the panel having a top face for supporting a plate and negative, and said panel being rigid in all directions parallel to its top face, positioning abutments above the top face of the panel, detachable fastening means connecting the positioning abutments to the panel with two abutments in position to serve as limit stops for an edge of the plate and the corresponding edge of the negative, and one abutment in position to serve as a limit stop for another and adjacent edge of the plate and corresponding edge of the negative, the positioning abutments extending above the panel for a height at least as great as the combined height of the plate and negative, and retaining means free of the negative and extending from each of the abutments inwardly across a portion of a plate and negative which are positioned with their edges against the abutment.

5. Photo exposure apparatus including a frame having a supporting panel therein and positioning abutments over the panel, the abutments being mounted on the panel and each abutment including a thin abutment plate at the bottom of the abutment and fixedly secured thereto and which extends in one or more directions beyond the remainder of the abutment, and adhesive tape extending over the thin abutment plate of each abutment and across adjacent portions of the panel to hold the abutment in position.

6. Photo exposure apparatus including a printing frame having a plate-supporting panel therein, and positioning abutments on the panel for locating the plate and an overlying negative carrier by contact with two and only two of the edges of the plate and carrier, there being two abutments along one edge of the plate and the corresponding edge of the carrier, and only one abutment along an adjacfinl .edge of the plate and the correspond ing edge of the carrier, detachable fastening means holding the abutments against the surface of the panel at any selected locations depending upon the sizes of the plate and negative carrier, and retaining means on each of: the abutments and at the tops of the abutments and extending inwardly across the plate and negative carrier and free of the plate and negative carrier and extending beyond the portions of the abutment with which the edges of the plate and carrier contact.

7. Photo exposure apparatus described in claim 6 and in which the detachable fastening means of each abutrnent includes a thin bottom plate connected to each abutment and resting on the panel, and adhesive tape extending across the thin bottom plate and across adjacent 6 areas of the panel; and in which the negative carrier comprises a plastic, light transmitting sheet having a negative thereon and which are secured to the carrier, said sheet being flexible but substantially uncompressible. References Cited in the file of this patent UNITED STATES PATENTS 997,418 Sayles July 11, 1911 1,181,163 Pilkington May 2, 1916 1,736,914 Huebner Nov. 26, 1929 1,761,863 Bassist June 3, 1930 1,914,127 Huebner June 13, 1933 2,223,357 Nahmens Dec. 3, 1940 2,372,493 Heyman Mar. 27, 1945 

